A tale of two syzygies

June 2012: The word syzygy — the alignment of the Sun and Earth with a third celestial object — ranks among the favorites of many astronomy enthusiasts. This month, observers have a chance to see the word in action twice.

By Martin Ratcliffe

By Alister Ling

Published: April 23, 2012

A partial lunar eclipse graces the sky above much of the Americas as well as eastern Asia and Australia on June 4.

Photo by Jamie Cooper

The word syzygy — the alignment of the Sun and Earth with a third celestial object — ranks among the favorites of many astronomy enthusiasts (particularly those who play the game hangman). This month, observers have a chance to see the word in action twice. On June 4, the Moon lies directly opposite the Sun in our sky and passes through our planet’s shadow. People across much of the Americas, the Pacific Ocean, Australia, and eastern Asia will see a partial lunar eclipse.

Less than 48 hours later, Venus passes between the Sun and Earth. This is Venus’ second solar transit in the past eight years but the last one until 2117. Observers nearly everywhere except eastern South America and western Africa will be able to watch at least part of this rare and historic event.

Following the transit, Venus moves into the morning sky and pairs with Jupiter in some spectacular predawn scenes. The evening sky has its own charm, with Mercury on display during twilight and Mars and Saturn prominent after darkness falls. Meanwhile, Pluto reaches opposition and peak visibility in late June. Although you will need a telescope to see the distant world, its position near a relatively bright star makes the task of finding it a bit easier than usual.

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